jQuery Pelo menos uma checkbox selecionada

Controlando o submit do formulário

by Salustiano Silva

HTML

<form>
    <label>
        <input type="checkbox" name="checkCountry[]" value="pt" class="check-group"> PT
    </label>
    <label>
        <input type="checkbox" name="checkCountry[]" value="en" class="check-group"> EN
    </label>
    <label>
        <input type="checkbox" name="checkCountry[]" value="de" class="check-group"> DE
    </label>
    <label>
        <input type="checkbox" name="checkCountry[]" value="es" class="check-group"> ES
    </label>
    <label>
        <input type="checkbox" name="checkCountry[]" value="fr" class="check-group"> FR
    </label>
    <p>
        <button>Enviar</button>
    </p>
</form>

JavaScript

$(function () {
    $('form').on("click", '.check-group', function (e) {
        if ($("form input:checkbox:checked").length >= 1) {
            $('form button').html('Enviar').prop('disabled', false);
        } else {
            $('form button').html('Tens que escolher o pais').prop('disabled', true);
        }
    });
})